Light-emitting diode (LED) array

ABSTRACT

An LED array having N light-emitting diode units (N≧3) comprises a permanent substrate, a bonding layer on the permanent substrate, a second conductive layer on the bonding layer, a second isolation layer on the second conductive layer, a crossover metal layer on the second isolation layer, a first isolation layer on the crossover metal layer, a conductive connecting layer on the first isolation layer, an epitaxial structure on the conductive connecting layer, and a first electrode layer on the epitaxial structure. The light-emitting diode units are electrically connected with each other by the crossover metal layer.

TECHNICAL FIELD

The application relates to an LED array, and more particularly to an LEDarray having N light-emitting diode units (N≧3).

REFERENCE TO RELATED APPLICATION

The application claims the right of priority based on TW applicationSer. No. 100110029 filed on Mar. 23, 2011, which is incorporated hereinby reference in its entirety and assigned to the assignee herein.

DESCRIPTION OF BACKGROUND ART

Recently, based on the progress of epitaxy process technology, thelight-emitting diode (LED) becomes one of the potential solid-statelighting (SSL) source. Due to the limitation of physics mechanism, LEDscan only be driven by DC power source. Thus the regulator circuit, buckcircuit, and other electronic devices are necessary for every lightingdevice using LED as lighting source to convert AC power source into DCpower source to drive LED. However, the addition of the regulatorcircuit, buck circuit, and other electronic device raises the cost oflighting device using LED as lighting source and causes the low AC/DCconversion efficiency and the huge lighting device package also affectthe reliability and shorten the lifetime of LED in daily use.

SUMMARY OF THE DISCLOSURE

The present application discloses an LED array comprising a permanentsubstrate, a bonding layer on the permanent substrate, a secondconductive layer on the bonding layer, a second isolation layer on thesecond conductive layer, a crossover metal layer on the second isolationlayer, a first isolation layer on the crossover metal layer, aconductive connecting layer on the first isolation layer, an epitaxialstructure on the conductive connecting layer, and a first electrodelayer on the epitaxial structure.

The present application further discloses an LED array comprising apermanent substrate, a bonding layer on the permanent substrate, a firstconductive layer on the bonding layer, a second isolation layer on thefirst conductive layer, a crossover metal layer on the second isolationlayer, a first isolation layer on the crossover metal layer, aconductive connecting layer on the first isolation layer, and anepitaxial structure on the conductive connecting layer.

The present application further discloses an Led array having Nlight-emitting diode units (N≧3) and the light-emitting diode units areelectrically connected with each other by the crossover metal layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1I are the cross sectional views of the LED array in accordanceof the first embodiment of present application.

FIGS. 1A′-1G′ are the top views of the first embodiment of LED arraydisclosed by present application.

FIGS. 2A-2I are the cross sectional views of the second embodiment ofLED array disclosed by present application.

FIGS. 2A′-2G′ are the top views of the second embodiment of LED arraydisclosed by present application.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present application discloses an LED array having N light-emittingdiode units (N≧3) comprising a first light-emitting diode unit, a secondlight-emitting diode unit in sequence to the (N−1)^(th) light-emittingdiode unit and an N^(th) light-emitting unit. The LED array furthercomprises a first area (I), the second area (II), and the third area(III). The first area (I) comprises the first light-emitting diode unit,the third area (III) comprises the N^(th) light-emitting diode unit, andthe second area (II) locates between the first area (I) and the thirdarea (III) and comprises the second light-emitting diode unit insequence to the (N−1)^(th) diode units.

The first embodiment discloses a first LED array 1 having threelight-emitting diode units. FIGS. 1A to 1I illustrate the crosssectional views and the FIGS. 1A′ to 1G′ illustrate the top views of thefirst embodiment of the first LED array 1. The method for manufacturingthe first LED array 1 comprises steps of:

-   -   1. Providing a temporary substrate 11, and forming an epitaxial        structure thereon. The epitaxial structure comprises a first        conductive semiconductor layer 12, an active layer 13, and a        second conductive semiconductor layer 14 as illustrated in FIGS.        1A and 1A′.    -   2. Next, forming multiple trenches 15 by partially etching the        epitaxial structure in the first area (I) and the second area        (II), and the epitaxial structure not etched forms multiple flat        planes 16, and the epitaxial structure of the third area (III)        is not etched as illustrated in FIGS. 1B and 1B′.    -   3. Forming a conductive connecting layer 17 on partial regions        of the flat planes 16, and the area of the flat planes 16        uncovered by the conductive connecting layer 17 forms multiple        pathways 18 as illustrated in FIGS. 1C and 1C′.    -   4. Forming a first isolation layer 19 on part of the conductive        connecting layer 17, the multiple pathways 18, and the side wall        of the multiple trenches 15, while the conductive connecting        layer 17 in the third area (III) and part of the conductive        connecting layer 17 in the first area (I) are not covered by the        first isolation layer 19. The conductive connecting layer 17 not        covered by the first isolation layer 19 in the second area (II)        is defined as a conductive region 20 as illustrated in FIGS. 1D        and 1D′.    -   5. Forming a crossover metal layer 21 on the first isolation        layer 19, the conductive region 20, in multiple trenches 15, and        on the conductive connecting layer 17 in the third area (III). A        part of the conductive connecting layer 17 in the first area (I)        is not covered by the crossover layer 21 in order to        electrically connect the second conductive layer 23 with the        second conductive semiconductor layer 14 in the following steps.        The region which is not covered by the crossover metal layer 21        in the second area (II) nearby the conductive region 20 is used        for electrical isolation as illustrated in the FIGS. 1E and 1E′.        Part of the crossover metal layer 21 in the first area (I)        extends to multiple trenches 15 and electrically connects to the        first conductive semiconductor layer 12. The crossover metal        layer 21 on multiple flat planes 16 and the pathways 18 in the        first area (I) is electrically isolated from the second        conductive semiconductor layer 14 by the first isolation layer        19. The crossover metal layer 21 on the conductive region 20 in        the second area (II) electrically connects with the second        conductive semiconductor layer 14 by the conductive connecting        layer 17. Part of the crossover metal layer 21 in the second        area (II) extends to multiple trenches 15 and electrically        connects to the first conductive semiconductor layer 12. The        crossover metal layer 21 on multiple flat planes 16 and the        pathways 18 in the second area (II) is electrically isolated        from the second conductive semiconductor layer 14 by the first        isolation layer 19. The crossover metal layer 21 in the third        area (III) is electrically connected with the second conductive        semiconductor layer 14 by the conductive connecting layer 17.    -   6. Forming a second isolation layer 22 on the crossover metal        layer 21 and the region a in the second area (II). But part of        the conductive connecting layer 17 in the first area (I) is not        covered by the second isolation layer 22 as illustrated in the        FIGS. 1F and 1F′.    -   7. Forming the second conductive layer 23 on the second        isolation layer 22 and part of the conductive connecting layer        17 as illustrated in the as illustrated in the FIGS. 1G and 1G′.    -   8. Forming a bonding layer 24 on the second conductive layer 23        which is bonded with a permanent substrate 25 by the bonding        layer 24 as illustrated in the FIG. 1H.    -   9. Removing the temporary substrate 11 to expose the first        conductive semiconductor layer 12 and roughening the surface of        the first conductive semiconductor layer 12. Next, etching        multiple pathways 18 from the first conductive semiconductor        layer 12 until the first isolation layer 19 is revealed in order        to form N light-emitting diode units. Among the N light-emitting        diode units, the first light-emitting diode unit locates in the        first area (I), the second to the (N−1)^(th) light-emitting        diode units locate in the second area (II), and the N^(th)        light-emitting diode unit locates in the third area (III). At        last, forming a first electrode layer 27 on the roughed surface        of the first conductive semiconductor layer 12 in the N^(th)        light-emitting diode unit. Thus an LED array 1 having N        light-emitting diode units electrically connected in serial by        the crossover metal layer 21 is formed as illustrated in FIG.        1I.

The second embodiment discloses a second LED array 2 having threelight-emitting diode units. FIGS. 2A to 2I illustrate the crosssectional views and the FIGS. 2A′ to 2G′ illustrate the top views of thesecond embodiment of LED array 2. The method for manufacturing thesecond LED array 2 comprises steps of:

-   -   1. Providing a temporary substrate 11, and forming an epitaxial        structure thereon. The epitaxial structure comprises a first        conductive semiconductor layer 12, an active layer 13, and a        second conductive semiconductor layer 14 as illustrated in FIGS.        2A and 2A′.    -   2. Next, forming multiple trenches 15 by partially etching the        epitaxial structure in the first area (I), the second area (II),        and the third area (III), and the epitaxial structure not etched        forms multiple flat planes 16 as illustrated in FIGS. 2B and        2B′.    -   3. Forming a conductive connecting layer 17 on partial regions        of the flat planes 16, and the area of the flat planes 16        uncovered by the conductive connecting layer 17 forms multiple        pathways 18 as illustrated in FIGS. 2C and 2C′.    -   4. Forming a first isolation layer 19 on part of the conductive        connecting layer 17, the multiple pathways 18, and the side wall        of the multiple trenches 15. The conductive connecting layer 17        in the second area (II) and the third area (III) which is not        covered by the first isolation layer 19 are defined as a        conductive region 20 as illustrated in FIGS. 2D and 2D′.    -   5. Forming a crossover metal layer 21 on the first isolation        layer 19, the conductive region 20, and in the multiple trenches        15 except those in the third area (III). A part of the first        isolation layer 19 in the first area (I) is not covered by the        crossover metal layer 21 in order to electrically isolate the        first conductive layer 26 from the second conductive        semiconductor layer in the following steps. The first isolation        layer 19 in multiple trenches 15 and flat planes 16 is not        covered by the crossover metal layer 21 in order to electrically        isolate the first conductive layer 26 from the second conductive        semiconductor layer 14 in the following steps as illustrated in        the FIGS. 2E and 2E′. A part of the crossover metal layer 21 in        the first area (I) extends to multiple trenches 15 and        electrically connects to the first conductive semiconductor        layer 12. The crossover metal layer 21 on multiple flat 16 and        the pathways 18 in the first area (I) is electrically isolated        from the second conductive semiconductor layer 14 by the first        isolation layer 19. The crossover metal layer 21 on the        conductive region 20 in the second area (II) electrically        connects with the second conductive semiconductor layer 14 by        the conductive connecting layer 17. A part of the crossover        metal layer 21 in the second area (II) extends into the multiple        trenches 15 and electrically connects to the first conductive        semiconductor layer 12. The crossover metal layer 21 on multiple        flat planes 16 and the pathways 18 in the second area (II) is        electrically isolated from the second conductive semiconductor        layer 14 by the first isolation layer 19. The crossover metal        layer 21 on the conductive region 20 in the third area (III)        electrically connects with the second conductive semiconductor        layer 14 by the conductive connecting layer 17. Besides, the        region b in the second area (II) and the third area (III)        adjacent to the conductive region 20 is not fully covered by the        crossover metal layer 21 which is used for electrical isolation.    -   6. Forming a second isolation layer 22 on the crossover metal        layer 21, the part of the first isolation layer 19 in the first        area (I), and on the region b which is not fully covered by the        crossover metal layer 21 in the second area (II). The second        isolation layer 22 does not cover the inner side of the trenches        15 in the third area (III), the first isolation layer 19 of the        multiple flat planes 16, and the region b which is not fully        covered by the crossover metal layer 21 in the third area (III)        as illustrated in the FIGS. 2F and 2F′.    -   7. Forming the first conductive layer 26 on the second isolation        layer 22, in the multiple trenches 15 in the third area (III),        on the first isolation layer 19 of the flat planes 16, and the        region b which is not fully covered by the crossover metal layer        21 in the third area (III) as illustrated in the FIGS. 2G and        2G′.    -   8. Forming a bonding layer 24 on the first conductive layer 26        which is bonded with a permanent substrate 25 by the bonding        layer 24 as illustrated in the FIG. 2H.    -   9. Removing the temporary substrate 11 to expose the first        conductive semiconductor layer 12 and roughs the surface of the        first conductive semiconductor layer 12. Next, etching multiple        pathways 18 form the first conductive semiconductor layer 12        until the first isolation layer 19 is revealed in order to form        N light-emitting diode units. Among the N light-emitting diode        units, the first light-emitting diode unit locates in the first        area (I), the second to the (N−1)^(th) light-emitting diode        units locate in the second area (II), and the N^(th)        light-emitting diode unit locates in the third area (III). Next,        etching the first conductive semiconductor layer 12 in the first        area (I) without the crossover metal layer 21 until the        conductive connecting layer 17 is revealed, and forming a second        electrode layer 28 on the conductive connecting layer 17. Thus        an LED array 2 having N light-emitting diode units electrically        connected in series by the crossover metal layer 21 is formed as        illustrated in FIG. 2I.

The temporary substrate 11 described in the above first and secondembodiments is made of, for example, gallium arsenide (GaAs), galliumphosphide (GaP), sapphire, silicon carbide (SiC), gallium nitride (GaN),or aluminum nitride. The epitaxial structure is made of an III-V groupsemiconductor material which is the series of aluminum gallium indiumphosphide (AlGaInP) or the series of aluminum gallium indium nitride(AlGaInN). The conductive connecting layer 17 comprises indium tinoxide, cadmium tin oxide, antimony tin oxide, indium zinc oxide,aluminum zinc oxide, and zinc tin oxide. The first isolation layer 19and the second isolation layer 22 can be made of an insulating materialcomprises silicon dioxide, titanium monoxide, titanium dioxide,trititanium pentoxide, titanium sesquioxide, cerium dioxide, zincsulfide, and alumina. The first conductive layer 26 and the secondconductive layer 23 can be made of silver or aluminum. The bonding layer24 is an electrically conductive material made of metal or its alloyssuch as AuSn, PbSn, AuGe, AuBe, AuSi, Sn, In, Au, or PdIn. The permanentsubstrate 25 is a conductive material such as carbides, metals, metalalloys, metal oxides, metal composites, etc. The crossover metal layer21 comprises metal, metal alloys, and metal oxides.

Although the present application has been explained above, it is not thelimitation of the range, the sequence in practice, the material inpractice, or the method in practice. Any modification or decoration forpresent application is not detached from the spirit and the range ofsuch.

What is claimed is:
 1. A light-emitting diode array having a first area,a third area, and a second area comprising: a permanent substrate; abonding layer on the permanent substrate; a second conductive layer onthe bonding layer; a second isolation layer on the second conductivelayer; a crossover metal layer on the second isolation layer; a firstisolation layer on the crossover metal layer; a conductive connectinglayer on the first isolation layer except the third area; an epitaxialstructure on the conductive connecting layer, wherein the epitaxialstructure further comprises a rough surface; and a first electrode layeron the epitaxy structure.
 2. The light-emitting diode array of claim 1,wherein the array comprises a first light-emitting diode unit, a secondlight-emitting diode unit in sequence to a (N−1)^(th) light-emittingdiode unit, a N^(th) light-emitting diode unit, and multiple pathwaysamong the N light-emitting diode, wherein N is not less than three;wherein the first light-emitting diode unit locates in the first area,the N^(th) light-emitting diode unit locates in the third area, and thesecond light-emitting diode unit in sequence to the (N−1)^(th)light-emitting diode unit locate in the second area located between thefirst area and the third area, wherein the N light-emitting diode unitsare electrically connected to each other by the crossover metal layer inseries.
 3. The light-emitting diode array of claim 1, wherein theepitaxial structure comprising: a second conductive semiconductor layer;an active layer on the second conductive semiconductor layer; a firstconductive semiconductor layer on the active layer; and a plurality oftrenches, wherein the trenches extend from the second conductivesemiconductor layer to the first conductive semiconductor layer exceptin the third area.
 4. The light-emitting diode array of claim 3, whereinthe first isolation layer locates on the side wall of the trenches andthe crossover metal layer extends into the trenches.
 5. Thelight-emitting diode array of claim 1, wherein the conductive connectinglayer in the third area locates between the epitaxial structure and apart of the crossover metal layer, and the conductive connecting layerin the first area locates between the epitaxial structure and the secondconductive layer.
 6. The light-emitting diode array of claim 1 furthercomprising: a conductive region located on the conductive connectinglayer in the second area and is not covered by the first isolationlayer; and an electrical isolation region not covered by the crossovermetal layer and is adjacent to the conductive region.
 7. Thelight-emitting diode array of claim 3, wherein the crossover metal layeris electrically isolated from the second conductive semiconductor layerby the first isolation layer.